Mechanical joining such as those using a bolt, rivet, screw and joining using an adhesive have been employed for the integration of a laminate comprising a reinforcement fiber and a thermosetting resin with an additional member. Mechanical joining has the drawback of difficulty in reducing the production cost since a preliminary working step of preparing the joint part is necessary, and application has also been limited by loosening generated by thermal expansion in a high temperature atmosphere and the thus impaired appearance. Meanwhile, joining using an adhesive has the drawback of difficulty in reducing the production cost since an adhesion step including preparation of the adhesive and coating the adhesive are required, and reliability in the adhesion strength was not always sufficient.
Of the thermoplastic resins, thermoplastic resins having an extremely high heat resistance called “super engineering plastics” are recently used as an alternative material for metals to reduce car weight in the field of automobiles. In the field of electric and electronic fields, durability resisting repetitive abrupt temperature change is required in view of equipment reliability and there is a demand for increase in continuous duty temperature in addition to the heat resistance.
Japanese Patent No. 3906319 discloses a laminate having continuous reinforcement fiber group and a matrix resin comprising a thermosetting resin and a thermoplastic resin as well as its production method. That laminate is the one prepared by melting or softening the thermoplastic resin contributing to the adhesion with the additional member at a temperature to which the thermosetting resin is heated to thereby form a thermoplastic resin adhesive layer on the surface of the fiber-reinforced thermosetting resin. In other words, the thermoplastic resin contributing to the adhesion with the additional member is melted or softened during the curing reaction of the thermosetting resin so that the thermoplastic resin adhesive layer is formed on the surface of the fiber-reinforced thermosetting resin. Japanese Unexamined Patent Publication (Kokai) No. 2007-254718 discloses a thermoplastic resin composite material wherein a highly heat-resistant thermoplastic resin comprising an assembly of highly flame-resistant monofilaments is embedded in the thermoplastic resin layer. As in Japanese Patent No. 3906319, in the composite structural material using that thermoplastic resin composite material, the thermoplastic resin contributing to adhesion with the additional member is melted or softened at the temperature at which the composite structural material is heated for the formation of the thermoplastic resin adhesive layer having the highly heat-resistant thermoplastic resin embedded therein. Since the thermoplastic resin contributing to the adhesion described therein needs to be melted or softened at the heating temperature, application as a member used in high temperature atmosphere had been strictly limited despite the good adhesion ability at normal temperature.
Japanese Unexamined Patent Publication (Kokai) No. H7-47152 discloses a racket frame made of a fiber-reinforcement resin comprising a fiber-reinforced thermosetting resin and a fiber-reinforced thermoplastic resin. In that racket frame, the thermosetting resin and the thermoplastic resin are in the form of a mixture at the boundary between the fiber-reinforced thermosetting resin and the fiber-reinforced thermoplastic resin, and the thermoplastic resin used has a melting point or a softening point higher than the heating temperature used in curing the thermosetting resin. However, the racket frame is obtained after curing the thermosetting resin by melting or softening the thermoplastic resin by further increase of the temperature, and an elongated time is required for the molding. In addition, the mixture layer of the thermosetting resin and the thermoplastic resin which serves the adhesive layer is formed in the interior of the racket frame and, therefore, applicability as a member serving adhesion with the additional member or as a member which is used in a high temperature atmosphere had been greatly limited.
Japanese Unexamined Patent Publication (Kokai) No. H7-149927 discloses a prepreg comprising a reinforcement fiber, a matrix resin, and a thermoplastic resin wherein a knitted fabric comprising a thermoplastic resin is present near the surface layer as well as its production method. The knitted fabric comprising the thermoplastic resin fiber described therein is used for the purpose of improving interlayer toughness, and in the molded article comprising such prepreg, the knitted fabric was required to be present in between the layers. Accordingly, use of a common integration technique was necessary to join with an additional member.
It could therefore be helpful to provide a laminate that exhibits high adhesion ability in high temperature atmosphere; an integrated molded article; and their production methods.